Resistance unit for controllers.



H. W. CHENEY.

RESISTANCE UNIT FOR CONTROLLERS,

APPLICATION FILED OCT. 6, 1909.

Patented Apr. 21, 1914.

' UNITED sTA Es;

PATENT OFFICE.

HERBERT W. CHENEY, OF MILWAUKEE, WISCONSIN, ASSIGNQR BY MESNE ASSIGN- M ENTS, TO ALLIS-CHALMERS MANUFACTURING COMPANY, A CORPORATION OI? I 'To all whom it may concern."

Be itknown that I, HERBERT W. CHENEY, a citizen of theUnited States, residing at Milwaukee, in. the county of Milwaukee and State of Wisconsin, haveinvented certain new and useful Improvements in Resistance Units for Controllers, of which-the following is a full, clear, and exact specification.

This invention relates to improvements in resistance units such as variable resistance units employed for starting or otherwise controlling the speed of dynamo-electric machines particularly, motors.

More specifi oally the invention relates to" resistance units arranged in the form of columns, such forexample as columns of carbon disks or other resistance members, the effective ohmic resistance ofwhich may be varied by varying the degree of compression between the members.

The object of the invention is to increase the radiation of heat from, theresistance units of the character indicated and to pro-' vide means whereby the natural upward flow of heated air along and away-from the resistance units is enhanced, sot-hat the tem perature of such units will not become excessive regardless of the amount'of heat generated in the same.

In carrying out my' invention I provide about the resistance unit which in use is arranged vertically or in the form of a column a number of heat radiating flanges which may have any desired -s acing longitudinally of the unit and may e formed of any desired material, preferably good heat conducting material and in these flanges I provide ventilating openings so that the formation of-pockets between the flanges is avoided and there will be a free and substantially unobstructed natural flow of air upward along the resistance unit through the flanges.

My invention may be briefly summarized as consisting in certain novel details of construction and combinations and arrangements of parts which will be describedin the specification and set forth in the appended claims.

For a better understanding of my invention reference is bad to the accompanying sheet of drawings wherein- Figure 1 is a partial diagrammatic view showing resistance units constructed in accordance with my inventlon and employed Specification er Letters Patent.

RESISTANCE UNIT FOR CONTROLLERS.

as a starting device for an induction motor. Fig. 2 is an enlarged transverse sectional view throughone of the resistance units showing the ventilating .openings in the flanges of the superposed heat radiating members in alinement. Fig. 3- is a similar view showing a slightmodification in the arrangement of the heat radiating members, the ventilating openings in the differentheat radiating members being relatively staggered.

Although I have-shown in the drawings resistance units of one type only and employed forone particular purpose, it is to be understood that the invention is not line-- ited to this type or to the particular use shown, but it may be employed with equal effect with various kinds of resistance members'having flanges or other heat radiating means between which the heated air might be pocketed.

Referring now-to the figures of the drawings, and first to Fig. 1, it will-be seen that I have shown in this instance a resistance device 10 having three resistance units 11, 12 and 13 in the form of columns, the lower ends of which are connected together by conductors l4 and 15 and he upper ends of which are connected by conductors 16, 17 and 18 to the slip rings of an induction motor 19 which is supplied with current from conductors 20 of a three phase circuit. It will be seen that these three resistance units are connected to the slip rings in Y formation. Each of the resistance units consists in this case of a column of disks 21 of resistance material-such as carbon, inclosed within a tube 22 preferably formed of good conducting material such as copper, the disks being separated from the tube by an insulating lining 23 as shown in Figs. 2 and 3.

The three resistance units are mounted on a base 21 forming a part of a-frame which includes vertical rods 21 and-a top plate 23 supported by the rods. Pivotally mounted upon the top plate 23 is an operating lever 24 by means of which the effective ohmic resistances of the three resistance units are adapted'to be simultaneously varied. This Patented Apr. 21, 1914. Application filedOctober 6, 1909. Serial No. 521,369.

lever 24 is provided with a pivoted rod 25 their upper ends with caps 27 and extending through these caps are plungcrs 28 on the lever from its normal position, the pluners 2S'will be forced downward into the dif-. erent tubes con'ipres'sing the carbon disks 21 so as to decrease the effective. resistance of. the pile or column of disks in each tube. 'Alsowhen the lever is raised the degree of compression between the disks is-decreased and consequently the total resistance of each column of disks is increased. The conductors 14 and 15 may be connected in any suitable manner to the lowermost disks of the three columns or units, and the conductors 16, 17 and 18 may be connected in any siIitable manner to the uppermost disks of the units or to the plungers 28 as desired. In the specific use of the resistance units shown in Fig. 1, to effectively bring the motor 19 up to the desired speed, the lever is graduallylowcred compressing the disks and reducing the ohmic resistances of, the units. When the motor is at the required speed the resistanceunits may be disconnected entirely from slip rings.-

Asshown clearly in Fi 1, each of the resistanceun-its is provided with a large number of heat radiating-members 29 which are preferably formed from good conducting, material such as copper, and each being formed with a. collar or. tubular portion 30 and with .a substantially horizontal circular flange 31. so that these members 29.will have large surfaces exposed to the air. It is to be understood that the heat radiating members may be constructed otherwise than hereshown, and a'nydesir'ed number may be providcd on each unit depending upon the amount of heat which is generated in the unit and the degree cit-temperature to which it is desired thatthe units be subjected. As will be apparent from Fig. 1 of the draw-' ing unless means is provided for permitting the heated air to escape'from between the flanges, the latter will form pockets for the heated air and the effective heat radiation will he comparatively small inasmuch-as these resistance units are vertically arranged.

To avoid the pocketing of air between the flanges each of'tl'ie' latter is provided, as shown clearly in Figs. 2 and 3, with a number of openings through ,which'a natural flow of air will take place upward alongthe unit. Theseopcnings may be arranged in alinementso that the upward' details shown but aim in my claims to coverall modifications which do not involve a d e parture from the spirit and scope of my invention.

lVhat I claim as new and desire to ecure by'Letters Patent is *l.. A resistance unit iiithe form of-a col-' umn and comprising a plurality of resistance .members, a tube inclosing said resistance members, a plurality of superposed heat radiating members spaced lengthwise of the unit and provided with flanges, said flanges having ventilating openings throughwhich airmay pass upwardly along the unit, the "openings in ad ace nt flanges being out of alinement. p

. 2. A resistance element having .a plurality of superposed spaced disks, said disks provided with openings, the openings of different disks being instaggered relation.

3. In a heat radiating device, a plurality ofsuperposed and spaced disks provided vwith openings, the openings in adjacent disks being out of alinement.

i. In a heat radiating device,a tubular element provided with a plurality of external plane flanges, said flanges being provided with openings arranged in staggered relation.

Milwaukee, Wis, Sept. 11, 1909.

In testimony whereof I aiiix my signature,-

in the presence of two witnesses.

HERBERT \V. CHENEY W'itnesses CiiAs. L. BYRON. Ron. E. R'ioLL. 

